As many as 1,500 cars and 10 acres on the 20-acre property were reported to have been scorched by flames as temperatures topped 100 degrees in the high desert, fire officials said.
Los Angeles County Fire Department Capt. Sheila Kelliher said early indications are that the fire started due to a malfunctioning hydraulic car crusher.
The fire was reported just before 3:30 p.m. Thursday on W Avenue H-8 and N. Sierra Highway in Lancaster.
About 180 firefighters were battling the blaze and by 8 p.m. it appeared the flames were mostly out, but smoke continued to pour from the yard. The L.A. County Fire Department reported a knockdown around 9:25 p.m.
The location was described as a car crusher site, with hundreds of crushed vehicles on fire and hundreds more threatened in the immediate vicinity.
One local business owner said he was told the fire started as a forklift was moving a vehicle and it ignited for unknown reasons.
The Lancaster sheriff's station issued a shelter-in-place order for the neighborhood between Division Street and Challenger Way north of Avenue I.
There were also sounds of explosions heard from the site.
A forklift was attempting to move some of the unburned vehicles away from the flames to create a buffer zone.
There were no injuries immediately reported. There were no evacuations ordered.